3 Gb/in(2) recording demonstration with dual element heads and thin film disks

• Published in: IEEE transactions on magnetics 1996-01, Vol.32 (1), p.7-12
• Main Authors: Tsang, Ching, Santini, H, McCown, D, Lo, J, Lee, R
• Format: Article
• Language: English
• ISSN: 0018-9464
• DOI: 10.1109/20.477542

We have successfully demonstrated magnetic recording at an areal density of 3 Gb/in(2) with narrow track inductive-write MR-read dual element heads on low noise Co alloy thin film disks. In this demonstration, the write head is a ten turn thin film inductive head with thick and narrow P2 pole-tips. The read head is a shielded ~1 mum trackwidth MR sensor soft-film biased in the read region for linearization and exchange-biased at the tail regions for magnetic stabilization. During recording tests, the heads were flown over low noise Co-alloy media at a clearance similar to that in the previous 1 Gb/in(2) recording experiment. Results showed good writability from the narrow track write head in terms of overwrite and hard transition shift. Readback yields symmetrical signals as large as 600 muV (p-p) and rolloff measurements showed 50% densities as high as 5000 fc/mm. Track profile and microtrack profile measurements showed the write and read trackwidths to be ~1.4 mum and ~1.1 mum respectively, with tight side-writing and side-reading characteristics. An overall assessment of the parametric recording results suggested areal density feasibility up to as high as 3 Gb/in(2). This projection was confirmed by error rate performance testing using a PRML channel with a digital filter and write precompensation. At a data rate of 4-5 Mb/s and at very low ontrack error, a linear density as high as 185 Kbpi and an optimized track pitch as narrow as 1.5 mum were achieved, corresponding to an areal recording density of ~3.1 Gb/in(2)